In the construction of structures or in the positioning of machines, it is necessary to support structures or equipment of heavy mass on fixed supports such as foundations or support slabs.
For example, support devices are known designed to transmit forces between the supported element and the support which are constituted by anchorages or articulations.
These devices transmit the forces integrally between the bearing structure and the borne element. This presents drawbacks in particular in the case where large stresses such as those accompanying an earthquake are transmitted to the supported element.
In particular, in the case of construction of nuclear reactors, for safety reasons one may be led to avoid the use of such support devices which can place the supported structures or equipment in danger, in the case of a considerable stress coming, for example, from the ground.
More elaborate support devices have therefore been conceived which absorb or limit such forces.
For example, the use of flat or curved sliding pads or of pads associated with stops or energy absorbers has been proposed.
Devices including support parts forming bearing tracks and elements such as balls have also been proposed, assuring in association the support of the structure.
Devices have been conceived, for example, associating two disks having concave surfaces with balls arranged between these two concave surfaces and pendular yokes with a spherical journal, for the support of structures or machines in order to reduce the forces transmitted to the borne element from the support.
If these devices indeed reduce the forces transmitted, they can only limit the relative movements of the bearer elements and of the borne element by the use of stops or energy absorbers, to avoid too large a deformation of the borne element.
On the other hand, systems with balls or with spherical bearings, if they have a good reaction to forces of any direction, are unusable as soon as the borne mass exceeds a certain threshold, i.e., when support by contact on a small surface is not possible.